U.S. patent number 10,256,783 [Application Number 15/714,395] was granted by the patent office on 2019-04-09 for dual-mode rf transmission frontend.
This patent grant is currently assigned to Taiwan Semiconductor Manufacturing Co., Ltd.. The grantee listed for this patent is Taiwan Semiconductor Manufacturing Co., Ltd.. Invention is credited to Hong-Lin Chu, Hsieh-Hung Hsieh, Tzu-Jin Yeh.
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United States Patent |
10,256,783 |
Chu , et al. |
April 9, 2019 |
Dual-mode RF transmission frontend
Abstract
A transmission frontend includes a modulator configured to
generate a modulated signal. A first selectable path is
electrically coupled to the modulator and is configured to generate
a first signal having a first power level. A second selectable path
is electrically coupled to the modulator and is configured to
generate a second signal having a second power level. The first
power level is greater than the second power level. A transformer
is electrically coupled to each of the first selectable path and
the second selectable path. An antenna is electrically coupled to
the transformer.
Inventors: |
Chu; Hong-Lin (Hsinchu,
TW), Hsieh; Hsieh-Hung (Taipei, TW), Yeh;
Tzu-Jin (Hsinchu, TW) |
Applicant: |
Name |
City |
State |
Country |
Type |
Taiwan Semiconductor Manufacturing Co., Ltd. |
Hsin-Chu |
N/A |
TW |
|
|
Assignee: |
Taiwan Semiconductor Manufacturing
Co., Ltd. (Hsin-Chu, TW)
|
Family
ID: |
62907269 |
Appl.
No.: |
15/714,395 |
Filed: |
September 25, 2017 |
Prior Publication Data
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|
|
Document
Identifier |
Publication Date |
|
US 20180212568 A1 |
Jul 26, 2018 |
|
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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62427501 |
Nov 29, 2016 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H03F
3/72 (20130101); H03F 3/45188 (20130101); H03F
3/195 (20130101); H04B 1/0483 (20130101); H03F
1/0277 (20130101); H03C 1/36 (20130101); H03F
2203/7209 (20130101); H03F 2200/451 (20130101); H03F
2203/72 (20130101); H03F 2200/541 (20130101); H04B
2001/0408 (20130101); H03F 2200/294 (20130101); H03F
2203/45731 (20130101) |
Current International
Class: |
H03F
3/72 (20060101); H03C 1/36 (20060101); H04B
1/04 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Nguyen; Duc M
Attorney, Agent or Firm: Duane Morris LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims benefit to U.S. Provisional Appl. Ser. No.
62/427,501, filed Nov. 29, 2016, entitled "DUAL-MODE RF
TRANSMISSION FRONTEND," which is incorporated herein in its
entirety.
Claims
The invention claimed is:
1. A transmission frontend, comprising: a modulator configured to
generate a modulated signal; a first selectable path electrically
coupled to the modulator, wherein the first selectable path is
configured to generate a first signal having a first power level; a
second selectable path electrically coupled to the modulator,
wherein the second selectable path is configured to generate a
second signal having a second power level, wherein the first power
level is greater than the second power level, and wherein the
second selectable path includes an impedance booster; and a
transformer electrically coupled to each of the first selectable
path and the second selectable path, wherein the impedance booster
is configured to increase an impedance on a first side of the
transformer when the second selectable path is selected; and an
antenna electrically coupled to the transformer.
2. The transmission frontend of claim 1, wherein the first
selectable path includes a first amplifier configured to provide a
first amplification and the second selectable path includes a
second amplifier configured to provide a second amplification,
wherein the first amplification is greater than the second
amplification.
3. The transmission frontend of claim 2, wherein first
amplification is in a range of 5 to 15 dBm.
4. The transmission frontend of claim 2, wherein the second
amplification is in a range of -5 to 5 dBm.
5. The transmission frontend of claim 2, wherein the first
selectable path is selected by providing the first amplifier with a
first voltage and the second selectable path is selected by
providing the second amplifier with a second voltage.
6. The transmission frontend of claim 1, wherein the impedance
booster includes at least one inductor electrically coupled to the
transformer.
7. The transmission frontend of claim 1, comprising a mixer
electrically coupled to the modulator.
8. The transmission frontend of claim 7, wherein the mixer is
configured to convert the input signal from a first frequency to a
second frequency.
9. The transmission frontend of claim 1, wherein the transformer
comprises a balun transformer.
10. The transmission frontend of claim 1, wherein the first signal
corresponds to a high-power implementation of a transmission
protocol and the second signal corresponds to a low-power
implementation of the transmission protocol.
11. The transmission frontend of claim 1, wherein the modulator
comprises a quadrature amplitude modulator.
12. A transmitter, comprising: a first selectable path configured
to receive a modulated signal, wherein the first selectable path
includes a first amplifier configured to amplify the modulated
signal from a first power level to a second power level, and
wherein the first amplifier is configured to receive a first signal
for selecting the first selectable path; a second selectable path
configured to receive the modulated signal, wherein the second
selectable path includes a second amplifier configured to amplify
the modulated signal from the first power level to a third power
level, wherein the second power level is greater than the third
power level, and wherein the second amplifier is configured to
receive a second signal for selecting the second selectable path,
and wherein the second selectable path includes an impedance
booster; a transformer electrically coupled to each of the first
selectable path and the second selectable path, the transformer
configured to receive the modulated signal from one of the first
selectable path or the second selectable path if selected, wherein
the impedance booster is configured to increase an impedance on a
first side of the transformer when the second selectable path is
selected; and an antenna coupled to the transformer.
13. The transmitter of claim 12, wherein first amplifier is
configured to provide an amplification in a range of 5-15 dBm.
14. The transmitter of claim 12, wherein the second amplifier is
configured to provide an amplification in a range of -5 to 5
dBm.
15. The transmitter of claim 12, wherein the first selectable path
is selected by setting the first signal to a first predetermined
voltage level and the second signal to zero voltage, and wherein
the second selectable path is selected by setting the second signal
to a second predetermined voltage level and the first signal to
zero voltage.
16. The transmitter of claim 12, wherein the impedance booster
includes at least one inductor electrically coupled to the
transformer.
17. The transmitter of claim 12, wherein the first signal
corresponds to a high-power implementation of a predetermined
transmission protocol and the second signal corresponds to a
low-power implementation of the predetermined transmission
protocol.
18. A method of transmission, comprising: receiving an input
signal; modulating the input signal to generate a modulated signal;
selecting one of a high-power selectable path or a low-power
selectable path; generating an amplified signal using the selected
one of the high-power selectable path or the low-power selectable
path; increasing an impedance on a first side of a transformer when
the low-power selectable path is selected; transforming the
amplified signal to a transmission signal having a frequency within
a predetermined frequency range; and transmitting the transmission
signal.
Description
FIELD
This disclosure related to radiofrequency (RF) transmission (TX)
frontends, and more specifically, to RF TX frontends configured for
transmission protocols having two or more power levels.
BACKGROUND
Several short-range communication protocols have been developed to
provide wireless communication between electronic devices, such as
near-field communication (NFC), Bluetooth.TM. (BT), Bluetooth Low
Energy (BLE), etc. Short-range communication protocols each operate
in predetermined frequencies and generally have a predetermined
power configured to provide short-range transmission. For example,
BT operates substantially in the 2400-2483.5 MHz range within the
ISM 2.4 GHz frequency band. As another example, BLE is a modified
form of BT communication that remains in sleep mode except when a
connection is initiated. As yet another example, NFC provides
communication in a 13.56 MHz band (as defined by ISO/IEC standard
18092).
Current TX frontends are configured to optimize one of a high-power
transmission or a low-power transmission. For example, high-power
frontends provide poor power efficiency for low-power signals, such
as BLE signals. Simultaneously, low-power frontends designed to
optimize power efficiency of low-power signals, such as BLE
signals, cannot provide output power for standard high-power
transmission. Current solutions provide optimization of only one of
two possible operating modes, low-power or high-power.
BRIEF DESCRIPTION OF THE DRAWINGS
Aspects of the present disclosure are best understood from the
following detailed description when read with the accompanying
figures. It is noted that, in accordance with the standard practice
in the industry, various features are not necessarily drawn to
scale. In fact, the dimensions of the various features may be
arbitrarily increased or reduced for clarity of discussion.
FIG. 1 illustrates a dual-mode TX frontend including a first
high-power transmission path and a second, low-power transmission
path, in accordance with some embodiments.
FIG. 2 is a graph illustrating output of the dual-mode TX frontend
of FIG. 1 using a low-power path, in accordance with some
embodiments.
FIG. 3 is a graph illustrating a peak current of the dual-mode TX
front end of FIG. 1 when transmitting a low-power signal, in
accordance with some embodiments.
FIG. 4 is flowchart illustrating a method of operation of the
dual-mode TX frontend of FIG. 1, in accordance with some
embodiments.
FIG. 5 illustrates a dual-mode TX frontend including a first,
high-power transmission path and a second, low-power transmission
path, in accordance with some embodiments.
FIG. 6 illustrates the dual-mode TX frontend of FIG. 5 configured
for a high-power transmission using the first transmission
path.
FIG. 7 illustrates the dual-mode TX frontend of FIG. 5 configured
for a low-power transmission using the second transmission
path.
FIG. 8 illustrates a passive I/Q up-conversion mixer, in accordance
with some embodiments.
FIG. 9 illustrates an active I/Q up-converter mixer, in accordance
with some embodiments.
DETAILED DESCRIPTION
Aspects of the present disclosure are best understood from the
following detailed description when read with the accompanying
figures. It is noted that, in accordance with the standard practice
in the industry, various features are not necessarily drawn to
scale. In fact, the dimensions of the various features may be
arbitrarily increased or reduced for clarity of discussion. Terms
concerning attachments, coupling and the like, such as "connected,"
"interconnected," "electrically connected," and "electrically
coupled" refer to a relationship wherein structures are
electrically attached or coupled to one another, either directly or
indirectly through intervening circuit elements, as well as both
wired or wireless attachments or relationships, unless expressly
described otherwise.
In various embodiments, a dual-mode radiofrequency transmission
frontend having a high-power path and a low-power path is
disclosed. The TX frontend includes an input configured to receive
a signal from one or more additional circuit elements. The input is
coupled to a modulator configured to provide modulation of the
input signal. The modulator is coupled to each of the high-power
path and the low power path. The high-power path includes one or
more circuit elements configured to provide a high-power output
signal corresponding to a first transmission protocol having a
first power. The low-power path includes one or more circuit
elements configured to provide a low-power output signal
corresponding to a second transmission protocol having a second
power. In some embodiments, the second transmission protocol is a
low-power version of the first transmission protocol. In some
embodiments, each of the high-power path and the low-power path are
coupled to an antenna.
FIG. 1 illustrates a dual-mode RF TX frontend 2 including a first,
high-power path 4 and a second, low-power path 6 in accordance with
some embodiments. The dual-mode RF TX frontend 2 receives an input
signal at an input 8. The input signal can be generated by one or
more additional circuits and/or circuit elements (not shown)
coupled to the input 8. For example, in some embodiments, the
dual-mode RF frontend 2 is coupled to one or more circuit elements
of a System-On-Chip (SOC) device. The dual-mode RF frontend 2 can
be integrated with the SOC device and/or electrically coupled to
the SOC. In some embodiments, the input 8 includes an amplifier
configured to amplify the input signal to a first predetermined
power level.
In some embodiments, the input signal is provided from the input 8
to a mixer 22. The mixer 22 is configured to mix the input signal
with one or more additional signals to generate a mixed signal. In
some embodiments, the mixed signal is generated by modifying the
frequency of the input signal. For example, the mixer 22 can
include a frequency mixer, such as, for example, a local
oscillator, configured to combine a predetermined frequency signal
with the input signal to modify the frequency of the input signal.
The mixer 22 can be configured to mix the input signal with one or
more carrier and/or predetermined frequency signals to generate a
signal suitable for modulation by a modulator 10. In some
embodiments, the mixed signal has a predetermined frequency
configured for one or more wireless protocols, such as, for
example, a frequency corresponding to BT/BLE transmission, NFC
transmission, and/or one or more other wireless protocols.
The mixed signal (or the input signal in embodiments omitting the
mixer 22) is provided to a modulator 10. The modulator 10 can
include any suitable signal modulator, such as an
amplitude-modulator, a quadrature amplitude modulator, a
phase-shift keying modulator, a minimum shift keying modulator, a
Gaussian frequency-shift keying modulator, a differential
quadrature phase shift keying (DQPSK) modulator, a .pi./4-DPQSK
modulator, an 8-DPQSK modulator, and/or any other suitable
modulator. The modulator 10 generates a one or more modulated
signals. For example, in some embodiments, the modulator 10 is a
quadrature modulator configured to generate a quadrature
amplification modulation (QAM) signal. The modulated signal is
provided to one of a high-power path 4 and/or a low-power path
6.
In some embodiments, the high-power path 4 is configured to
generate a high-power signal configured for transmission in
accordance with a first transmission protocol, such as BT protocol,
an NFC protocol, and/or any other suitable transmission protocol.
The high-power path 4 includes one or more circuit elements
configure to convert the modulated signal from a first power level
received from the modulator 10 to a second power level
corresponding to a predetermined power level of the first
transmission protocol. For example, in some embodiments, the
high-power path 4 includes a high-power power-amplifier 12. The
high-power power-amplifier 12 is configured to convert the
modulated signal from a first power level to a second power level,
greater than the first power level. The high-power amplifier 12 can
be configured to boost the input received from the modulator 10 to
any suitable level. For example, in some embodiments, the
high-power amplifier 12 is configured to provide an amplification
of about 10 dB, although it will be appreciated that other
amplifications are within the scope of this disclosure. In some
embodiments, the high-power amplifier 12 is an operational
amplifier. The high-power amplifier 12 is electrically coupled to a
transformer 16.
In some embodiments, the low-power path 6 is configured to generate
a low-power signal suitable for transmission according to a second
transmission protocol having a lower transmission power than the
first protocol. For example, in some embodiments, the second
transmission protocol is a low-power version of the first
transmission protocol, such as BLE protocol. The low-power path 6
includes one or more circuit elements configured to convert the
modulated signal from the first power level to a third power level.
The third power level is less than the second power level generated
by the high-power path 4. For example, in some embodiments, the
low-power path 6 includes a low-power amplifier 18 and an impedance
booster 20. The low-power amplifier 18 is configured to provide
amplification of a signal received from the modulator 10 to a third
power level.
In some embodiments, low-power path 6 is configured to maintain the
same power level as the output of the modulator 10 (e.g., the first
power level and the third power level are equal). For example, in
some embodiments, the low-power amplifier 18 is configured to
provide an amplification of about 0 dB (e.g., no amplification),
and instead functions as a switch to control the low-power path 6.
The output of the amplifier 18 is provided to the impedance booster
20. The impedance booster 20 is coupled to the transformer 16 and
is configured to increase the impedance of a first side 16a of the
transformer 16. For example, in some embodiments, the impedance
booster 20 is an inductor in series with the first side 16a of the
transformer 16. The increased inductance of the first side 16a
compensates for the lower power level of the low-power path 6 when
converting the low-power signal to a signal suitable for
transmission in a BT/BLE frequency.
The high-power path 4 and the low-power path 6 are selectively
controlled such that only one of the high-power signal or the
low-power signal are provided to the transformer 16. In various
embodiments, each of the high-power path 4 and the low-power path 6
can include one or more circuit elements configured to selectively
enable the respective path 4, 6. For example, in some embodiments,
each of the high-power path 4 and/or the low-power path 6 can
include a switch configured to control operation of the respective
path 4,6. In some embodiments, one or more elements of each of the
high-power path 4 and the low-power path 6 are configured to
receive one or more signals, such as a selector signal and/or a
variable power signal, to selectively control the associated
circuit elements.
For example, in some embodiments, the high-power amplifier 12
receives a first input voltage (not shown) and the low-power
amplifier 18 receives a second input voltage (now shown). For
example, when a high-power transmission is desired, the first input
voltage is set to a predetermined value sufficient to provide a
first predetermined amplification of the modulated signal. For
example, the first input voltage can be set to about 1.5 V during
operation to provide a first amplification power. The first
amplification power can be any suitable amplification power, such
as an amplification of about 5 to 15 dBm, for example, 10 dBm. The
second input voltage is set to 0 V, which prevents the low-power
amplifier 18 from amplifying the modulated signal. Similarly, in
another example, when BLE transmission is desired, the second input
voltage is set to a second predetermined value and the first input
voltage is set to zero. For example, the second input voltage can
be set to about 0.8 V during operation to provide a second
amplification power, such as an amplification of about -5 to 5 dBm,
for example, 0 dBm. Although specific examples are provided herein,
it will be appreciated that other predetermined voltages and/or
amplification powers can be selected and are within the scope of
this disclosure. In some embodiments, the first input voltage and
the second input voltage can have the same set voltage value.
The selected one of the high-power path 4 or the low-power path 6
provides an amplified signal to the transformer 16. The transformer
16 is configured to convert the amplified signal received at a
first side 16a of the transformer 16 to a transmission signal at a
second side 16b. In some embodiments, the transmission signal is a
signal in the BT/BLE frequency range. In some embodiments, the
transformer 16 has a first impedance on a first side 16a and a
second impedance on a second side 16b configured to transform from
a first frequency of the amplified signal to a second,
predetermined frequency of the transmission signal (e.g., an
impedance boosting topology). The second side of the transformer 16
is coupled to an antenna 14. The transformer 16 can include any
suitable transformer, such as, for example, a balun
transformer.
The antenna 14 is configured to transmit the transmission signal at
the predetermined frequency. For example, in some embodiments, the
antenna 14 is configured to transmit a high-power BT signal and/or
a low-power BLE signal. In some embodiments, the antenna 14 is a
dedicated antenna. In other embodiments, the antenna 14 is a shared
antenna and is shared by one or more additional transmission and/or
receive frontends (not shown) coupled to one or more additional
and/or alternative circuit elements.
In some embodiments, the mixer 22 is an I/Q up-conversion mixer.
FIG. 8 illustrates a passive I/Q up-conversion mixer 22a, and FIG.
9 illustrates an active I/Q up-conversion mixer 22b, in accordance
with some embodiments. Each of the passive I/Q up-conversion mixer
22a and the passive I/Q up-conversion mixer 22b is configured to
receive a first set of inputs 72a-72b and a second set of inputs
74a-74b. In some embodiments, the first set of inputs 72a, 72b
corresponds to in-phase (I) components of a received signal and the
second set of inputs 74a, 74b correspond to quadrature (Q)
components of the received signal. The I/Q up-conversion mixers
22a, 22b are configured to generate a positive RF output signal
component 76a and a negative RF output signal component 76b in
response to the received I/Q components 72a-74b.
In some embodiments, the passive I/Q up-conversion mixer 22a
includes a set of first transistors 78a-78d (collectively "first
set 78") and a set of second transistors 80a-80d (collectively
"second set 80") coupled to each of the I component inputs 72a, 72b
and the Q component inputs 74a, 74b. For example, as shown in FIG.
8, a first transistor 78a of the first set 78 and a first
transistor 80a of the second set 80 each have a first drain/source
terminal coupled to a positive I component input 72a. Similarly, a
second transistor 78b from the first set and a second transistor
80b from the second set 80 each have a first drain/source terminal
coupled to a negative I component input 72b. In some embodiments,
each of the first transistors 78a-78d have a second drain/source
terminal coupled to the positive RF output 76a, and each of the
second transistors 80a-80d have a second drain/source terminal
coupled to the negative RF output 76b. An inductor 82 is coupled
between the positive RF output 76a and the negative RF output
76b.
In some embodiments, the gates of each of the first transistors
78a-78d and the second transistors 80a-80d are coupled to a local
oscillator input 84a-86b associated with the positive and/or
negative I/Q component 72a-74b. For example, in the illustrated
embodiment, a first transistor 78a receives a positive I component
input 72a at a first source/drain terminal and a positive local
oscillator input 84a at a gate terminal. Similarly, a second
transistor 80a receives a positive I component input 72a at a first
source/drain terminal negative local oscillator input 84b at a gate
terminal. The local oscillator inputs 84a-86b are configured to
control operation of the respective transistors 78a-78d, 80a-80d to
generate the RF outputs 76a, 76b.
The active I/Q up-conversion mixer 22b of FIG. 9 is similar to the
passive I/Q up-conversion mixer 22a of FIG. 8, and similar
description is not repeated herein. In some embodiments, the active
I/Q up-conversion mixer 22b includes a set of third transistor
82a-82d coupled between the first and second transistors 78a-80d
and the I/Q component inputs 72a-74b. In some embodiments, a gate
of each of the transistors 82a-82d is coupled to one of the I/Q
component inputs 72a-74b. For example, in the illustrated
embodiment, a gate of a first transistor 82a is coupled to a
positive I component input 72a, a gate of a second transistor 82b
is coupled to a negative I component input 72b, a gate of a third
transistor 82c is coupled to a positive Q component input 74a, and
a gate of a fourth transistor 82d is coupled to a negative Q
component input 74b. A first drain/source terminal of each of the
transistors 82a-28d is coupled to a respective pair of the first
set of transistors 78a-78d and the second set of transistor
80a-80d. A second drain/source terminal of each transistor 82a-82d
is coupled to ground. In some embodiments, the inductor 82 is
coupled to a voltage input 86. The voltage input provides an
increased voltage across the inductor 82 as compared to the passive
I/Q up-conversion mixer 22a of FIG. 8.
FIG. 2 is a Smith graph 100 illustrating an impedance
transformation of the BT/BLE frontend 2. As shown in FIG. 2, a
constant standing wave ratio (SWR) 102 illustrates the increase in
impedance of the BT/BLE signal from the first side 16a of the
transformer to the second side 16b. The constant SWR 102
illustrates a complex relationship between the impedance of the
first side 16a and the second side 16b. The position of the
constant SWR 102 on the left-side of the Smith graph 100 indicates
an increase in impedance from the first side 16a to the second side
16b of the BT/BLE frontend 2. The transformation causes attenuation
of the signal, which is illustrated by the spiral path of the
constant SWR 102.
FIG. 3 is a graph 200 illustrating operation of one embodiment of a
dual-mode RF TX frontend 2 during a low-power signal transmission,
in accordance with some embodiments. The peak current 202 is
plotted in mA against the antenna output 204 plotted in dBm, and
the voltage draw 206a, 206b of the low-power path 6. The voltage
draw 206a, 206b is shown as a power ratio (dBm) 206a and a voltage
power (dbV) 206b. Each of the peak current 202, the antenna output
204, and the voltage draw 206 are plotted against the power input
(v.sub.in dBm) of the dual-mode RF TX frontend 2. As shown in FIG.
3, in this embodiment, the low-power path 6 is configured to
provide an amplification of 0 dBm (e.g., the low-power path has an
amplifier 18 configured to act as a switch without amplifying the
modulated signal received from the modulator) at a predetermined
input voltage. The low-power amplifier 18 has a predetermined input
voltage about 0.8 V, resulting in a peak current 202 of about 3.75
mA. The dual-mode RF TX frontend operates at about 33.3% efficiency
during a low-power transmission. Similarly, in the illustrated
embodiment, during a high-power signal transmission, the high-power
path 4 is configured to provide an amplification of about 10 dBm.
The high-power amplifier receives a predetermined input voltage of
about 1.5 V, resulting in a peak current of about 22 mA. The
dual-mode RF TX front end operates at about 30.3% efficiency during
a high-power transmission. In some embodiments, the high-power
transmission is a BT transmission and the low-power transmission is
a BLE transmission.
FIG. 4 is a flowchart illustrating a method of operation 300 of the
dual-mode RF TX frontend 2, in accordance with some embodiments. At
a first step 302, an input signal is received at an input 8 of the
dual-mode RF TX frontend 2. The input 8 can include an amplifier
configured to amplify the received input signal to a first power
level. At step 304, the input signal is modulated, for example, by
a modulator 10. The input signal can be modulated using any
suitable modulation, such as, for example, an amplitude-modulator,
a quadrature modulator, a phase-shift keying modulator, a minimum
shift keying modulator, a Gaussian frequency-shift keying
modulator, a differential quadrature phase shift keying. (DQPSK)
modulator, a .pi./4-DPQSK modulator, an 8 DPQSK modulator, and/or
any other suitable modulator. In some embodiments, modulation of
the input signal optionally includes mixing the input signal using
a mixer 22 prior to modulation by the modulator 10 to modify the
frequency of the input signal.
At step 306, one of a high-power path 4 or a low-power path 6 is
selected. In some embodiments, the path 4, 6 is selected by
providing input power to at least one circuit elements, such as an
amplifier, in the one of the selected high-power path 4 or
low-power path 6. For example, in some embodiments, the high-power
path 4 includes a high-power amplifier 12. The high-power path 4 is
selected by providing a first predetermined input voltage to the
high-power amplifier 12. As another example, in some embodiments,
the low-power path 6 includes a low-power amplifier 18. The
low-power path 6 is selected by providing a second predetermined
input voltage to the low-power amplifier 18. The second
predetermined voltage is less than the first predetermined input
voltage. In some embodiments, the high-power path 4 and/or the
low-power path 6 can be selected using one or more additional
circuit elements or signals, such as one or more switches, enable
signals, variable power signals, and/or any other suitable control
elements and/or signals.
If the high-power path 4 is selected at step 306, the modulated
signal is provided to one or more circuit elements configured to
generate a high-power signal at step 308. For example, in some
embodiments, the high-power path 4 includes a high-power amplifier
12 configured to amplify the generated modulated signal to a power
level suitable for transmission according to a first transmission
protocol having a first power standard. In some embodiments, the
high-power amplifier 12 has an amplification in a range of about 5
to 15 dBm, for example 10 dBm. If the low-power path 6 is selected
at step 306, the modulated signal is provided to one or more
circuit elements configured to generate a low-power signal at step
310. For example, in some embodiments, the low-power path 6
includes a low-power amplifier 18 configured to amplify the
modulated signal to a power level suitable for transmission
according to a second transmission protocol having a second power
standard. The second power standard is less than the first power
standard. In some embodiments, the second transmission protocol is
a low-power version of the first transmission protocol. The
low-power path 6 further includes an impedance modifier 20
configured to modify the impedance of a first side 16a of a
transformer 16. In some embodiments, the low-power amplifier 18 has
an amplification in a range of about -5 to 5 dBm, for example, 0
dBm, and passes the modulated signal from the modulator 10 to the
transformer 16 at a constant power. Although embodiments are
discussed herein including an amplification of the high-power path
4 of about 10 dBm and the lower path 6 of about 0 dBm, it will be
appreciated that the high-power path 4 and/or the low power path 6
can include any suitable amplification range. For example, in some
embodiments, the high power path 4 can include an amplification in
a range of about 30 dBm to about 0 dBm, such as 25 dBm to 5 dBm, 20
dBm to 7 dBm, 15 dBm to 10 dBm, and/or any other suitable
amplification. As another example, in some embodiments, the low
power path 6 can include an amplification in a range of about 20
dBm to about -10 dBm, such as 15 dBm to -5 dBm, 10 dBm to -3 dBm, 4
dBm to 0 dBm, and/or any other suitable amplification or range of
amplifications.
At step 312, a signal from the selected one of the high-power path
4 or the low-power path 6 is transformed to a frequency suitable
for transmission in as a BT/BLE signal. In some embodiments, the
signal is transformed by a transformer 16, such as a balun
transformer. The transformer 16 includes a first impedance side 16a
coupled to each of the high-power path 4 and the low-power path 6
and a second impedance side 16b coupled to an antenna.
At step 314, the high-power/low-power signal is transmitted by the
antenna 14. In some embodiments, the antenna 14 is configured to
transmit the high-power/low-power signal at any suitable frequency,
such as a frequency shared by each of the first transmission
protocol and the second transmission protocol. For example, in some
embodiments, the first transmission protocol is a BT protocol and
the second transmission protocol is BLE protocol. The power of the
transmitted signal is determined by the selection of one of the
high-power path 4 or the low-power path 6.
FIG. 5 illustrates a dual-mode TX frontend 2a including a first
signal path 4a and a second signal path 6a, in accordance with some
embodiments. The first signal path 4a is a high power signal path
and the second signal path 6a is a low-power signal path. The
dual-mode TX frontend 2a receives a positive input signal at a
first input 8a and a negative input signal at a second input 8b.
The positive and/or negative input signals can be generated by one
or more additional circuits and/or circuit elements, such as, for
example, a mixer 22, 22a, 22b as illustrated in FIGS. 1, 8, and 9,
respectively.
In some embodiments, the first input 8a is coupled to a first
high-power selection circuit 52a and a first low-power selection
circuit 54a and the second input 8b is coupled to a second
high-power selection circuit 52b and a second low-power selection
circuit 54b. Each of the high-power selection circuits 52a, 52b and
the low-power selection circuits 54a, 54b includes a capacitor
56a-56d, a resistor 58a-58d coupled between the capacitor 56a-56d
and a voltage input 60a, 60b, and a switch element 62a-62d. The
capacitor 56a-56d and the resistor 58a-5a8d associated with each
switch element 62a-62d provide a predetermined response for each of
the selection circuits 52a-54b.
For example, in some embodiments, each of the high-power selection
circuits 52a, 52b are coupled to a first voltage input 60a. When
the first voltage input 60a is set to a predetermined value, the
capacitors 56a, 56b associated with the high power selection
circuits 52a, 52b are charged, connecting the switch elements 62a,
62b of the high power selection circuits 52a, 52b to respective
positive and negative RF inputs 8a, 8b. Similarly, in some
embodiments, each of the low-power selection circuits 54a, 54b are
coupled to a second voltage input 60b. When the second voltage
input 60b is set to a predetermined value, the capacitors 56c, 56d
associated with the low-power selection circuits 54a, 54b are
charged, connecting the switch elements 62c, 62d of the low-power
selection circuits 54a, 54b to respective positive and negative RF
inputs 8a, 8b.
FIG. 6 illustrates the dual-mode TX frontend 2a configured to
transmit a signal using the high-power transmission path 4a, in
accordance with some embodiments. The low-power path 6a (which is
not selected) is greyed out to indicate that the low-power path 6a
is not active in this configuration. In the illustrated embodiment,
the first voltage input 60a is set to a predetermined value to
charge the first and second capacitors 56a, 56ba associated with
each of the first switch element 62a and the second switch element
62b. After the first and second capacitors 56a, 56b are charged,
the gates of each of the switch elements 62a, 62b are coupled to
respective RF inputs 8a, 8b. An RF signal received at each of the
RF inputs 8a, 8b acts as a control signal for the switch elements
62a, 62b. The switch elements 62a, 62b control a high-power
amplifier 12a including a second set of transistor elements 64a,
64b. When the second set of transistor elements 64a, 64b are
activated, an oscillating high-power transmission voltage is
provided across a first side 16a of a transformer 16. For example,
when the RF input signal is positive, the first switch element 64a
is on, which turns on the first transistor element 64a of the
high-power amplifier 12a. The first transistor element 64a provides
a positive amplified signal on the first side 16a of the
transformer 16. Similarly, when the RF signal is negative, the
second switch element 64b is on, which turns on the second
transistor element 64b of the high power amplifiers 12a. The second
transistor element 64b provides a negative amplified signal on the
first side 16a of the transformer 16.
FIG. 7 illustrates the dual-mode TX frontend 2a of FIG. 5
configured to transmit a signal using the low-power transmission
path 6a, in accordance with some embodiments. The high-power
transmission path 4a is shown greyed out, as the high-powered
transmission path 4a is not active in this configuration. In the
illustrated embodiment, the second voltage 60b is set to a
predetermined value to charge the third and fourth capacitors 56c,
56d associated with each of the third switch element 62c and the
fourth switch element 62d. After the capacitors 56c, 56d are
charged, the gates of each of the switch elements 62c, 62d are
coupled to the respective RF inputs 8a, 8b. An RF signal received
at the RF inputs 8a, 8b acts as a control signal for switch
elements 62c, 62d. The switch elements 62c, 62d are configured to
pass the RF input signal received at RF inputs 8a, 8b to a first
impedance booster 66a coupled to the third switch element 62c and a
second impedance booster 66b coupled to the fourth switch element
62d. The impedance boosters 66a, 66b adjust the impedance of the RF
input signal prior to the RF input signal being provided to the
transformer 16. In some embodiments, the impedance boosters 66a,
66b include inductors.
In some embodiments, a transmission frontend is disclosed. The
transmission frontend includes a modulator configured to generate a
modulated signal. A first selectable path is electrically coupled
to the modulator and is configured to generate a first signal
having a first power level. A second selectable path is
electrically coupled to the modulator and is configured to generate
a second signal having a second power level. The first power level
is greater than the second power level. A transformer is
electrically coupled to each of the first selectable path and the
second selectable path. An antenna is electrically coupled to the
transformer.
In some embodiments, a transmitter is disclosed. The transmitter
includes a first selectable path configured to receive a modulated
signal and a second selectable path configured to receive the
modulated signal. The first selectable path includes a first
amplifier configured to amplify the modulated signal from a first
power level to a second power level. The first amplifier is
configured to receive a first signal for selecting the first
selectable path. The second selectable path is configured to
amplify the modulated signal from the first power level to a third
power level. The second power level is greater than the third power
level. The second amplifier is configured to receive a second
signal for selecting the second selectable path. A transformer is
electrically coupled to each of the first selectable path and the
second selectable path. The transformer is configured to receive
the modulated signal from one of the first selectable path or the
second selectable path if selected. An antenna is electrically
coupled to the transformer.
In some embodiments, a method of transmission is disclosed. The
method includes the steps of receiving an input signal, modulating
the input signal to generate a modulated signal, selecting one of a
high-power selectable path or a low-power selectable path,
generating an amplified signal using the selected one of the
high-power selectable path or the low-power selectable path,
transforming the amplified signal to a transmission signal having a
frequency within a predetermined frequency range, and transmitting
the transmission signal.
The foregoing outlines features of several embodiments so that
those skilled in the art may better understand the aspects of the
present disclosure. Those skilled in the art should appreciate that
they may readily use the present disclosure as a basis for
designing or modifying other processes and structures for carrying
out the same purposes and/or achieving the same advantages of the
embodiments introduced herein. Those skilled in the art should also
realize that such equivalent constructions do not depart from the
spirit and scope of the present disclosure, and that they may make
various changes, substitutions, and alterations herein without
departing from the spirit and scope of the present disclosure.
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